1. Field of the Invention
The invention relates to recirculating pumps; and, more particularly, to an impeller pump having dual motors driving dual counterrotating impellers to increase the efficiency and flow rate of the fluid flow of the pump.
2. Description of the Prior Art
Recirculating pumps are well known in the prior art. Such pumps include a motor rotating an impeller shaft, the impeller shaft having an impeller secured thereto rotating within an impeller housing connected to the motor housing. The impeller housing has an inlet for introducing water therein and an outlet whereby the impeller blades force water thereout under pressure. Various types of such pumps are known and are of varying horespower. These pumps may be of the open air or submersible type and may be operated in various positions depending on the environment. The gallons per hour of fluid flow is thus increased by incresing the horsepower of such pumps.
As a general rule, the only way to increase fluid flow of such prior art pumps, or to provide a back-up for a pump in case of failure, is to increase the number of such pumps. This of course adds appreciably to the cost.
In U.S. Pat. No. 2,810,345 to Englesson, dual motor pumps are employed having a single inlet and outlet. The pump of Englesson is primarily used to run either of the two impellers so that one impeller can be used as a back-up for the other. The arrangement of Englesson eliminates the complicated valve systems used before Englesson to alternately run two pump units. There is no suggestion of using the two impellers to increase the efficiency of the fluid flow.
In U.S. Pat. No. 3,935,971 to Papoff et al, two interdependent pumps are used where one pump or both pumps may be operated and the flow rate of each pump is adjusted to provide for the mixing of two materials. Two pumps are necessary to carry out the invention and no suggestion is made for using the two pumps to increase the efficiency of the water flow output.
Two entirely independent pumps used to either pump water from one or the other, or both, is disclosed in U.S. Pat. No. 3,602,611. Again, two separate pumps are necessary and no suggestion is made as to increasing the efficiency of the fluid flow.
There is thus a need for a pump which obtains the increased water flow provided by a plurality of pumps without the need for separate independent pumps.